1. Field of the Invention
The present invention relates to lighting strips and methods for making the same, and in particular to extrusions and extrusion methods for such light strips.
2. Description of Related Art
Flexible printed circuit boards have been manufactured in strips that are populated with light emitting diodes. The strips can be mounted in a transparent tubular sleeve that is easily mounted in a variety of locations. These lighting strips can be placed inside cabinets, along corridors to light a walkway, or any place where a compact lighting source is required.
Light emitting diodes have relatively small forward voltage drops and therefor require a voltage conversion unit such as a transformer, which adds to the complexity of the installation. Also known light strips have included ASICs to regulate the applied voltage, but these ASICs tend to be large, generate much heat, and have a tendency to pull off the underlying, flexible printed circuit board.
Known lighting strips have flexible circuit boards that carry both the lighting elements and buses that carry power throughout the strip. When the strip is relatively long, the buses must carry significant current that tends to heat a flexible circuit board and degrades the performance of the adjacent LEDs, possibly causing them to fail. Many applications require an especially long lighting strip. In such cases a number of shorter strips are spliced together and mounted in a common sleeve, end to end. In this case the buses on each strip are serially connected and must carry current for all the lighting elements in the several strips. Such a common bus carries even more current, and generates even more heat that seriously affects the lighting elements.
Also, it can be difficult to mount in a single sleeve, long lighting strips or a number of serially connected lighting strips.
See also U.S. Pat. Nos. 3,786,173; 4,032,210; 4,990,098; 5,032,960; 5,296,648; 5,337,225; 5,559,681; 5,681,179; 5,833,358; 6,113,248; 6,244,893; 6,673,292; 6,773,286; 7,249,980; 7,753,577; 8,052,303; 8,262,250; 8,398,262; 8,635,769; 8,641,229; and 8,714,772.